There are 7 nickels and 8 dimes, if you look closely at the procedure, you can see how <em>x </em>is established for the nickels (0.05) and <em>y </em>for the dimes (0.10).
The easiest way to find the solution is to plug in one of the coordinates that is located in the shaded area into each equation. If the equations make sense, as they do in the orange option, you have your answer.
<span>given:
bull's eye radius= x
width of surrounding rings=y
solution:
Radius of the circle=x+4y
Area of the outermost ring=Area of the circle-Area of the penultimate ring
=Ď€(x+4y)^2-Ď€(x+3y)^2
=Ď€(x^2+8xy+16y^2-x^2-9y^2-6xy)
=Ď€(2xy+7y^2)
hence the area of the outermost ring in terms of x and y is π(2xy+7y^2).</span>
